Way worth the cost. This game proves that Harmonix is still numero uno.
This game has four different instruments for you to play cooperatively, and it works ot fantastically. The vocals are tuned exactly to the song so you can practice adjusting your pitch ike a true singer (I never knew my voice was so sexy), the guitar is not too difficult but just right and rarely results in frantic button mashes and bleeding calluses, the bass is easy and makes you really want to take up the instrument, and then there are the drums. Yes, thes drums are a game all in itself. Just think: Drum Hero. Harmonix combined fou of the greatest rhythm games into one unbelievable package nd create a fun and friendly atmosphere (unless your bandmtes suck).
I find the Solo moe to be as fun, if not more fun then GH's single player campaign. The main reason is this: Your own characters are on the stage. No more are the days of disliking your Guitar Hero's appearences. Now, your very own rock persona is unleashed into the game's amazing visuals. Watch as your rocker performs all of the stunts you wish you could do, and pat yourself on the back, not Johnny Napalm or Judy Nails/ Pandora clone.
Band mode is alot more complicated then you might expect. There are no clear-cut paths to take. You and your group of one, two, or three other people make decisions and play through various gigs,keeping loyal to your true fans or selling out to the man for profits. The choice is up to you. Gambling on your winnings is also key (i.e. double or nothing on cash, fans, etc.).
Pulling failing bandmates out of oblivion is a nice feature, but poorly executed on the drums, due to the fact that drums can only use star-power on certan drum-fills. So, basically, don't rely on thm to pull you out fro oblivion. Another problem with the game is so random character they use to fill in positions not occupied by created characters (imagine a large, tall, metal-head complete with armor and face paint. Now imagine him singing in a falsetto to Flyleaf or the Yeah Yeah Yeahs...). It can create some wierd shows, and doesn't always match the mood of the song (headbanging maniacally to Here It Goes Again, lol).
Other than that, grab some friends or random guys online and hve a bast playing the best music game ever created.